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Food and climate change - save or doom the world while eating

Published 18th October 2009 - 12 comments - 4514 views -

Our contributions to the greenhouse effect via the food we eat is touched upon every now and then by media and public debate. Vegetarians usually blame meat eaters and buying local is touted as an obvious solution. It's a bit more complicated than that so this article sums up the results from a scientific study on exactly this subject. These numbers, details and recommendations need more attention. Not just to heighten the level of discourse but because as they say:

"Current trends in food choices point toward increased environmental effects."

Some of us may be seeing more and more environmentally friendly and affordable choices. Perhaps we're just looking for them which the majority still isn't?

The Greenhouse built from food

Producing food is one of the basic human activities. In any form it is a process of consumption - even ancient slash and burn agriculture involved the removal of an ecosystem carbon sink (the forest) - but some forms are a lot less straining on our resources than others. One meal can emit nine times as much greenhouse gas as another of similar caloric content. How so?

While carbon dioxide (CO2) is the most important greenhouse gas (GHG) significant contributions are also made by methane (CH4, ~14%-25% of emissions [2 , 3]) and nitrous oxide (N2O, ~8% of emissions [3]). Methane is a product of natural materials decomposing without oxygen present - the occasional tree that dies and fall into a lake (naturally occurance of rot under water contributing miniscule GHGs), from the farts of many plant eating animals (due to their special cellulose digestion but significant contributions from industrial breeding only), from storage of manure (again: low oxygen rot) and from growing rice in flooded conditions (low oxygen and microorganisms). Nitrous oxide is produced by microbial transformation in soils and manure - especially when plenty of nitrogen is present. Nitrogen is often in local surplus from over-fertilization but it is actually also a by-product of the manufactur of fertilizer.

So, even if our food production lowered its emissions of CO2 it'd still feed the greenhouse effect. Currently agriculture is the main source of the increase in atmospheric methane (~50%) and nitrous oxide (~60% to much higher in [3]). I'll skip the math in the middle and go straight to some dos and don'ts (mostly specific to a Western consumer but quite general).

Eat less red steaks

Emission of methane is particularly tied to the large scale production of meat (and consequently the dairy "by-products"... and rice). Livestock and their manure is guilty of about one twentieth (1/20) of the total GHG emissions. Cattle is the main problem because if its extreme emissions of methane by enteric fermentation. So, although pigs emit more methane via their manure, cattle in total emits about 3.8 times as much non-CO2 GHG per carcass weight. Per kilo of final edible product it accumulates to 30 kilos of CO2 equivalents (the measure of comparison between foods from here).

"[...] the consumption of 1 kg domestic beef [...] represents automobile use of a distance of ~160 km (99 miles)."

Don't even think about flying in that Argentine steak.

Of course, beef has good proteins. But comparing the GHG-wise efficiency of beef as a means of protein production to other food products it is actually the least effective. We can get our proteins from cereals, legumes and certain fish without causing climate change.

Don't eat the codLeave it in the ocean. "20 kg Cod" by *saipal

One fish we shouldn't rely on for protein, though, is the cod. Well to begin with it's on the verge of extinction due to over-fishing and warming waters (at least in the Baltic and North Seas, marine ecologists predict it may reestablish itself in the Barents Sea [4]). But for each kilo of cod caught about 9 kg (yes nine kilos) of GHGs are emitted because trawling for them is fuel-intensive. This makes cod about as climate unfriendly as pork.

Although use of fossil fuel is increasingly "punished" (discouraged financially) and promises of protection of endangered species are handed out left and right cod fishing is profitable due to heavy subsidies by the European Union.

And things are relative: While I may have portrayed pork as a reasonable substitute for beef above, cod and pork emits approximately the same amount of GHGs (8.8 to 9.3 kg CO2 equivalents).

The tropics are a spice

The flying Argentine steak is of course nasty. But basically, flying around with our nutrients is just not very smart. Anything flown from one half of the world to another will have a very bad GHG budget. Even fresh fruit; each kilo of which leaves 11 kilos of CO2 right in the atmosphere if transported by plane. Many of our primary exotics - bananas, oranges - are shipped in by boat though, which is much, much more carbon friendly than planes.

The good solution is to eat locally produced food that doesn't require much transport at all. Should be common sense, really. Such products also has less need for demanding storage and temporary processing.

Consider the cheese and eggs too

Domestically produced cheese emits about as much GHG CO2 equivalents as tropical fruits. And although a on a diffent scale entirely even eggs have a less than impressive figure (~23% of that of cheese). On the one hand especially eggs, however, are a source of protein. On the other hand both products are probably a bit too prevalent in many Western diets for other general health and nutritional reasons (fats, cholesteroles, salmonella).

There are many pros and cons to consider. Do we compose the climate friendly recipe by eating only low GHG emitting foods? Or do we just adjust our diets a little bit here and there? Besides preferences and willingness to change, one important thing to consider is our need for protein. Let's face it: We're not going to convert to hut dwelling veganism all of us just yet.

The perfect recipe?

About those 'little changes' first: Chicken production emits only about 4.3 kg CO2 equivalents per kilo of meat. So, while still polluting, it could substitute some other meat meals while significantly lowering GHG emissions. (Small scale chicken production also holds some additional benefits such as pest control in plantations and food waste recycling. Chicken also lives anywhere in the world.) It is a relatively efficient source of proteins (~50 grams per kg GHG).

Another "substitute food" - having annoyed the cod fans above, perhaps - could be herring. At least in countries with herring rich waters. Fishing for herring is much less fuel demanding than fishing for cod. Thus, it also becomes a very efficient source of proteins (~145 grams per kg GHG).

Speaking of protein efficiency there is one clear winner: domestically produced whole wheat (~160 grams per kg GHG due to only 0.63 kg CO2 equivalents per kilo of food).Wheat - started the party and could save it too. "Wheat Field [E-X-P-L-O-R-E-D]" by KevinLallier.

Secondly, soy need being mentioned as it even after shipping by boat (0.92 kg CO2 per kilo of food emitted) it delivers some 120 grams of protein per kg GHG emitted. Almost as good a budget goes for Italian pasta: compared to soy it additionally emits a bit of nitrous oxide but still delivers about 50 grams of protein per kg GHG emitted.

At last, the clear winners: fresh carrots, potatoes and honey (in north Europe at least). These foods emit very little GHGs (0.42, 0.45 and 0.46 kg CO2 eqivalents of GHGs per kilo of food emitted respectively). They also provide some source of protein as well as other important nutritional ingredients. And honey is deliciously sweet.

Also, honorable mention to apples. The ones in your garden especially, but even when sailed in by boat the GHG budget is OK.

It is important to remember though, that this study didn't investigate every crop and livestock known to man, only a select set of representative and common choices. Pleas do comment with suggestions for other foods to avoid or prefer. Or even better: An actual recipe of low GHG emissions.

And finally: I personally don't really like either cod, herring, chicken or cheese myself. But I'm not vegetarian either as I really like beef, milk, eggs and other not too glorious foods unmentioned in this research (coffee to begin with). On a positive note, I love apples and honey. But I just summed up a research article - not advertising my tastes here. As may have been evident, I'm no cook either.

One reflection made by the authors is the possibility of forcing fast food producers to "extend" their beefs with plant proteins. Actually, this could have a major beneficial impact. They also propose more information (propaganda) to the public about those dietary changes that will be beneficial to both human as well as environment.

Sources:

First of all...

ResearchBlogging.org Carlsson-Kanyama, A., & Gonzalez, A. (2009). Potential contributions of food consumption patterns to climate change American Journal of Clinical Nutrition, 89 (5), 1704-1709 DOI: 10.3945/ajcn.2009.26736AA





Additionally...

This post was chosen as an Editor's Selection for ResearchBlogging.org

This post was chosen as an Editor's Selection for ResearchBlogging.org

 

Category: Agriculture, Greenhouse Gases, | Tags: agriculture, food, co2, researchblogging,



Comments

Daniel Nylin Nilsson on 18th October 2009:

In the Lord of the Rings there is one guy (Radagast?) who lives from milk and honey, only. That sounds pretty nice, then? wink

Good post on a very important topic!

Tyrone Slothrop on 18th October 2009:

@ D N Nilsson: the guy you mean is Beorn, he also eats bread and he’s in The Hobbit, not The Lord Of The Rings (Though I think he is mentioned in the Appendices to LOTR)

back on topic:

Buggerrr! Chicken is better than cheese??? and here I was, feeling smug about my eco-vegan life style. And wtf… Chicken is better than EGGS?!?

Benno Hansen on 19th October 2009:

According to Wikipedia “Beorn lived on simple diet of bread, honey and clotted cream.
“

Dairy (and eggs) can be produced as a “by-product”. The sole purpose of an animal isn’t necessarily just to be eaten.

Beorn was very sustainable, huh! Not like the bad bad lumberjack orcs.

10in10Diet.com on 02nd November 2009:

Have a look at my web site. It’s a simple, cheap, vegetarian, healthy, green and convenient system. Your freezer will be stacked with single servings of tasty food, all versions of stuff you might order in a roadhouse when trying to avoid meat. It’s like eating in a different third world country every day.

Enjoy!
Lynn Shwadchuck
http://www.10in10diet.com/

Benno Hansen on 02nd November 2009:

Follow-up: Sustainable Food blog @ Change.org / Brouhaha Over Meat’s Impact on Climate:
“The discussion of reducing meat consumption as a means of fighting climate change is ruffling some high-profile feathers in several places.”

Free fast food coupons on 06th November 2009:

I can see that you are putting a lot of time and effort into your blog and detailed articles! I am deeply in love with every single piece of information you post here. Will be back often to read more updates!

Asad on 06th November 2009:

Thanks for taking the time to post such a detailed and informative article. It has given me a lot of inspiration and I look forward to more like this in the future.
Fast food coupons

Paul Montariol on 17th November 2009:

I eat fish 5 times a week.
It is a good thing for our social security.
You have 50% cancers less!
Cancer is very expensive and we need for money!

Pamela Drew on 19th November 2009:

Anything that involves food politics is delicious for me and this was an especially wonderful piece Benno, thank you.

One of the issues we face here in the USA, is that the agribusiness operations have no cost to wasteful or toxic behavior.  We are a land of obese consumers and fast food diets where the truth about what the true cost of cheap eats is to human health or the environment.

Perhaps one of the clearest examples is the factory farm waste we are drowning in, while our media turns a blind eye and cues the fast food and drug ads.  Scorecard keeps score though!

Almost two trillion pounds of animal waste are produced per year nationally. An increasing amount of this animal waste is produced by intensive livestock operations, which are really more factories than farms.

Common animal waste treatment practices used by these livestock factories are often inadequate to protect our drinking water and environment, posing one of America’s serious pollution problems.

See Scorecard’s overview of animal waste problems.  http://www.scorecard.org/env-releases/aw/

I can never resist adding a link or two!!

Paul Montariol on 19th November 2009:

@ Pamela
You just say what I try to explain.
The competitiveness is in the system.

I have told what I think here:
http://climatechange.thinkaboutit.eu/think2/post/indirect_competitiveness_source_of_great_richness

Mike Licht on 25th January 2010:

Mark Bittman uses the term “Lessmeatarian”:

http://www.markbittman.com/lose-weight-save-the-planet-become-a-lessmeatarian

And provides recipes.

PdfOk on 26th August 2010:

The reference scenario projects the agricultural system to the year 2060 with no climate change and with no major changes in the political or economic context of world food trade. It assumes:
  * UN medium population estimates (10.2 billion by 2060) (UN, 1989; International Bank for Rural Development/World Bank, 1990).
  * 50% trade liberalization in agriculture (e.g.. removal of import restrictions) introduced gradually by 2020.
  * Moderate economic growth (ranging from 3.0%/year in 1980-2000 to 1.1%/year in 2040-60).
  * Technology projected to increase yields over time (1990-2060). Cereal yields of world total, developing countries and developed countries were assumed to increase annually by 0.7%, 0.9%, and 0.6%, respectively.

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